WordPress JS scrolling within pages

menu.php

<?php
// replace basic links by scrolling ones if this is the page linked
$actual_url = (isset($_SERVER['HTTPS']) ? "https" : "http") . "://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
$url_path = str_replace('/', '\/', parse_url($actual_url, PHP_URL_PATH));
$main_menu = preg_replace('~<a href="' . $url_path . '#scroll-(.*?)">(.*?)<\/a>~i', '<a href="#" data-scrollto="#$1">$2</a>', $main_menu);

WordPress JS scrolling within pages.js

jQuery(function($) {
	// get vertical offset of element by selector
	var getElOffset = function(selector) {
		var offset;
		if(selector === '#top') {
			return 0;
		} else {
			offset = $(selector).offset();
			if(typeof offset === 'undefined') return false;

			offset_top = offset.top - $('header').outerHeight();
			if($('#wpadminbar').length) {
				offset_top -= $('#wpadminbar').outerHeight();
			}

			return offset_top;
		}
	},

	scrollToEl = function(selector) {
		var offset = getElOffset(selector);

		$('html, body').animate({
        	scrollTop: offset,
    	}, 400);
	};

	// bind scrolling links
	$('a[data-scrollto]').on('click', function(e) {
		var selector = $(this).data('scrollto');

		e.preventDefault();
		if($(selector).length > 0 || selector === '#top') {
			// disable mobile menu if that we the trigger and scroll
			$('body').removeClass('mobile-nav-active');
			scrollToEl(selector);
		}
	});

	// if URL contains scrolling hash, scroll there
	if(window.location.hash !== '' && window.location.hash.substring(0, 8) === '#scroll-') {
		var location = '#' + window.location.hash.substring(8);
		setTimeout(scrollToEl, 500, location);
	}

});